W. Travis McMaken, The Sign of the Gospel: Toward an Evangelical Doctrine of Infant Baptism after Karl Barth, Emerging Scholars (Fortress, 2013), 20.
Infant baptism was practiced in extremis in the early Christian centuries, but it was always something of a practice in search of a theology. By pressing it into service in his dispute with the Pelagians, Augustine “provided the theology that led to infant baptism becoming general practice for the first time in the history of the church.” This was not his intent. In fact, he argued that it was already the church’s general practice, and had been since the time of the apostles. Other sources considered above belie this claim. Further, the logic of his argument moved away from the practice of infant baptism and toward the establishment of his doctrine of original sin and guilt. However, once “original sin was established as the basic framework for thinking, then it was natural for it to become the principal reason for infant baptism.” This resulted in infant baptism quickly becoming established as a standard practice—and, indeed, the definitive form of baptism—rather than an in extremis concession. As Karen Spierling notes, “infant baptism was an established practice of the Christian church” within one hundred years of Augustine’s dispute with the Pelagians.To see precisely how I define the sacramental argument, you’ll have to buy the book. So, go do that.
In this way, Augustine provided Christian theology with the first of its two great arguments in support of infant baptism, namely, the sacramental argument . . .